Refactor GitHub workflows and prepare release 0.12.0 #511

Job	Run time
Tests (Python-3.8)	7m 2s
slow-test-detection	1s
Tests (Python-3.9)	7m 2s
Tests (Python-3.10)	7m 12s
Checks / Version Check	45s
Checks / Build Documentation	53s
Checks / Linting (Python-3.8)	1m 0s
Checks / Type Checking (Python-3.8)	58s
Checks / Linting (Python-3.9)	1m 4s
Checks / Type Checking (Python-3.9)	57s
Checks / Linting (Python-3.10)	1m 9s
Checks / Type Checking (Python-3.10)	54s
Checks / Linting (Python-3.11)	59s
Checks / Type Checking (Python-3.11)	53s
Checks / Tests (Python-3.8, Exasol-7.1.9)	3m 54s
Checks / Tests (Python-3.9, Exasol-7.1.9)	4m 18s
Checks / Tests (Python-3.10, Exasol-7.1.9)	3m 53s
Checks / Tests (Python-3.11, Exasol-7.1.9)	3m 59s
Gate 1 - Regular CI	1s
metrics / Generate Status Report	52s
run-slow-tests	0s
Gate 2 - Allow Merge	0s
	47m 46s

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